The Great Schism, also known as the East-West Schism, was the event that divided "Chalcedonian" Christianity into Western (Roman) Catholicism and Eastern Orthodoxy. Though normally dated to 1054, when Pope Leo IX and Patriarch Michael I excommunicated each other, the East-West Schism was actually the result of an extended period of estrangement between the two bodies of churches. The Church split along doctrinal, theological, linguistic, political, and geographic lines, and the fundamental breach has never been healed.